So I'm on a trip right now. As I was on the freeway, I noticed my engine power and rpm band fluctuating. It was mild at first but got worse as I carried. I finally stopped and took it to a shop since I was desperate and didn't want to end up on the side of the road. Had a fuel system cleaning. Drove off and things seemed fine for a couple miles and then it started again and become really bad. This all started into this trip and never before.

I filled the tank prior to setting off so I'm not sure if it might be bad fuel or my fuel pump is going. Anyone have any idea what this might be?

Failing fuel pump. Stale fuel in the lines from before your trip. Timing belt skipped a tooth (though this would be MAJOR obvious, I speak from experience). I don't know what car you have so I'm gonna put gunked spark plugs on that list too. Maybe a coil on the way out.

Again, no clue what car you have, can't be very specific to your application.

Failing fuel pump. Stale fuel in the lines from before your trip. Timing belt skipped a tooth (though this would be MAJOR obvious, I speak from experience). I don't know what car you have so I'm gonna put gunked spark plugs on that list too. Maybe a coil on the way out.

Again, no clue what car you have, can't be very specific to your application.

It's an 01' Cavalier. 143k on it. I put more gas in it when I arrived at my destination. Took it out for abit later when I went out for dinner and it gave me no fuss. The issue arised so quickly, I'm still hoping it was something as simple as bad fuel. As I said, took it to a Jiffylube out of shear desperation and the only solution they could provide from immediate inspection was to clean the fuel system. Told me it could take 100 miles before really seeing a result.

Will see if the problem persists tomorrow on the freeway heading to my interview and then returning home. Hoping it's not the fuel pump.

Thanks Kitsune. I'm not mechanically savvy and can't mess with that right now. When I get back home, I'll try to take a look at it.

Temp was running in the normal range the whole drive. No warning lights or anything of that sort came up.

Not sure what you're sorry for. If it's because I'm in a Cavalier though, yeah, appreciated. It's one of those things however that I plan to replace once financial means align better for me, hopefully much sooner than later.

Temp was running in the normal range the whole drive. No warning lights or anything of that sort came up.

Not sure what you're sorry for. If it's because I'm in a Cavalier though, yeah, appreciated. It's one of those things however that I plan to replace once financial means align better for me, hopefully much sooner than later.

I was referring more to the outside air temperature, but if you didn't see the gauge do anything funky then I'm assuming it was fine. While overheating wouldn't affect the performance of an older car by a ton (they'll blow themselves up instead), cars with fancy computer doohickeys like yours will pull all sorts of crap to try to save the engine if it starts running out of spec. Was a shot in the dark.

I'd agree with the dude above who added the MAF to the possibilities. I had a 280Z with a messed-up wiring harness to the airflow meter and it was hilarious the difference between 'working' and 'not working'. I think I still have a video showing it on my youtube channel, haha. And yes, I'm apologizing for the Cavalier. I drove one of those in 2004 (I think) and it was not an enjoyable experience.

I was referring more to the outside air temperature, but if you didn't see the gauge do anything funky then I'm assuming it was fine. While overheating wouldn't affect the performance of an older car by a ton (they'll blow themselves up instead), cars with fancy computer doohickeys like yours will pull all sorts of crap to try to save the engine if it starts running out of spec. Was a shot in the dark.

I'd agree with the dude above who added the MAF to the possibilities. I had a 280Z with a messed-up wiring harness to the airflow meter and it was hilarious the difference between 'working' and 'not working'. I think I still have a video showing it on my youtube channel, haha. And yes, I'm apologizing for the Cavalier. I drove one of those in 2004 (I think) and it was not an enjoyable experience.

So how long had your Cavalier been sitting before this trip?

Outside air temp was 74.

The car gets driven consistently which is why the problem surprised me as everything was just green yesterday.

If it's random for no reason and completely goes away for no reason, that's electrical/electronic. Our PT Cruiser has done similar things (like reporting that we had 0 gas about 20 miles after filling up, or a complete loss of power on the freeway which magically fixed itself after a restart).

Your car's OBDII, so go borrow a scanner and see if your car threw any codes. It probably didn't, but I'm still gonna say this is 100% electrical gremlin status.

Keep us posted on what you find! Hopefully it isn't a timing belt issue like Nomake mentioned. Just like Nomake said though, it would be very obvious if that was the case. Performing necessary maintenance on your vehicle is important. If you have done that already then you should be fine. If not, you should get on that asap.

I got the car back home and yesterday went to work taking the intake assembly off.

Things I noted about the problem was that it only occurred at freeway speeds. Did some more research on the MAF sensor and am alittle confused by the way the 2.2 engine might have it set up. The wiring hooked to the air duct (picture 2), attached to what looked like a light but this didn't appear to be the sensor. You're going to have to forgive my mechanical ignorance here.

Turns out, there is no MAF sensor in the 2.2 Cavalier. Doing more research, I found it could be the manifold absolute pressure sensor which brought things back to square one almost as I'll have to get a multimeter to test it.

I also cleaned my air filter for good measure.

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That 'light' is likely an inlet temperature sensor. Figures that your car has a MAP instead of a MAF. Hahaha. Yeah, get that tested. Also, a multimeter is just a darn good thing to have in general. I can't tell you how many times having one has saved my bacon. I keep one in my car at all times and have since the SVX. One resides in the electrical box of the Maverick just in case I have to find a wiring fault.